The "SIM800C" is a GSM/GPRS module manufactured by SIMCom Wireless Solutions, which is part of the SIMCom family of communication modules. It is widely used in applications involving mobile connectivity, such as embedded systems, IoT devices, and remote control systems.
Pinout and Functions for SIM800C
The SIM800C module typically comes in a VQFN-28 (Very thin quad flat package with 28 pins). Below is a detailed explanation of each of the 28 pins and their functions.
Pin Number Pin Name Pin Function/Description 1 VCC Power supply pin (3.4V to 4.4V) 2 GND Ground pin 3 TXD Serial data transmit pin (UART) 4 RXD Serial data receive pin (UART) 5 RTS Request To Send (for hardware flow control) 6 CTS Clear To Send (for hardware flow control) 7 DTR Data Terminal Ready (for hardware flow control) 8 DSR Data Set Ready (for hardware flow control) 9 RI Ring Indicator (used for indicating incoming call) 10 NC No Connection (not used) 11 VBAT Battery voltage supply pin (to power the module) 12 BATT_SENSE Battery voltage sensing pin (connected to battery for monitoring) 13 VDDIO Supply for the digital IOs (1.8V or 2.8V depending on the model) 14 SIM_RST SIM card reset pin 15 SIM_CLK SIM card clock pin 16 SIM_DIO SIM card data input/output pin 17 SIM_CMD SIM card command pin 18 ANT antenna pin (connects to the antenna for GSM connectivity) 19 NC No Connection (not used) 20 NC No Connection (not used) 21 NC No Connection (not used) 22 NC No Connection (not used) 23 NC No Connection (not used) 24 NC No Connection (not used) 25 NC No Connection (not used) 26 NC No Connection (not used) 27 NC No Connection (not used) 28 NC No Connection (not used)Note: The unused pins (marked as NC) do not have a specific function and are typically left unconnected.
Pin Function Details
VCC: Supplies the power to the module. It needs a stable voltage between 3.4V and 4.4V. GND: The ground pin, typically connected to the system’s ground. TXD/RXD: These are the transmit and receive pins for UART communication. TXD sends data from the module to an external device, and RXD receives data from the external device. RTS/CTS: These pins are used for hardware flow control, ensuring that data is sent and received at a proper rate. DTR/DSR: DTR is used to control the power-up and power-down sequence. DSR is used for hardware handshake purposes. RI: It is used to detect incoming calls, and it can generate an interrupt when the module receives an incoming call. VBAT: It is the main power input to the module. Typically, this pin is connected to the positive terminal of the power source (such as a battery). BATT_SENSE: Monitors the battery voltage. It allows the module to adjust operation based on the available voltage. VDDIO: This provides power to the digital IO pins of the module. It can be 1.8V or 2.8V, depending on your application. SIMRST, SIMCLK, SIMDIO, SIMCMD: These pins are used for interfacing with the SIM card. SIMRST resets the SIM, SIMCLK provides the clock for the SIM, SIMDIO is for data input/output, and SIMCMD is for command communication with the SIM. ANT: This pin connects to the external antenna for communication with the GSM network.Frequently Asked Questions (FAQ)
Q: What is the power supply requirement for the SIM800C? A: The SIM800C requires a power supply between 3.4V and 4.4V for proper operation. It’s crucial to maintain this voltage range. Q: What type of UART is supported by SIM800C? A: The SIM800C supports a standard UART communication interface , with pins for TXD and RXD for data transmission and reception. Q: Can I connect the SIM800C directly to a microcontroller? A: Yes, the SIM800C can be connected to a microcontroller using UART or hardware flow control pins (RTS, CTS). Q: How do I connect the SIM card to the module? A: The SIM card interfaces through the SIMRST, SIMCLK, SIMDIO, and SIMCMD pins, which are used to communicate with the card. Q: What antenna should I use with the SIM800C? A: You should use a GSM antenna with an impedance of 50 ohms, and it should be connected to the ANT pin. Q: What happens if I connect the SIM800C to a higher voltage than 4.4V? A: Over-voltage could damage the module. The voltage should not exceed 4.4V for safe operation. Q: Is the SIM800C capable of handling 3G networks? A: No, the SIM800C supports GSM and GPRS networks but does not support 3G or LTE. Q: How do I reset the SIM800C module? A: The module can be reset using the SIM_RST pin or by sending a software reset command over the UART interface. Q: How can I monitor the battery voltage in SIM800C? A: You can monitor the battery voltage using the BATT_SENSE pin.Q: What type of SIM card should I use with the SIM800C?
A: The SIM800C supports a standard 2FF (mini-SIM) card.Q: Can the SIM800C be powered by a battery?
A: Yes, the module is designed to be powered by a battery connected to the VBAT pin.**Q: What is the function of the *RI* pin?**
A: The RI pin is used to signal incoming calls or SMS messages.Q: Is there a method for controlling the power of the SIM800C?
A: Yes, the module can be powered on/off by controlling the DTR pin.Q: Can the SIM800C be used for SMS and voice communication?
A: Yes, the SIM800C supports SMS and voice communication over the GSM network.**Q: What is the role of the *RTS* and CTS pins?**
A: These pins are used for hardware flow control, ensuring proper data transfer between the module and other devices.Q: How should I connect the UART for data transmission?
A: Use the TXD and RXD pins for UART communication. Ensure that the TXD of the module connects to the RXD of the external device, and vice versa.**Q: What voltage should I apply to the *VDDIO* pin?**
A: The VDDIO pin should be supplied with 1.8V or 2.8V depending on your application requirements.Q: How can I check if the SIM800C is successfully registered on the network?
A: You can check network registration status by sending the AT+CREG? command.Q: Can I interface multiple SIM800C modules simultaneously?
A: Yes, you can interface multiple SIM800C modules as long as each has its own communication interface (UART) or is controlled via multiplexing.Q: How do I handle incoming and outgoing calls?
A: Incoming and outgoing calls can be handled using AT commands, with call status information available on the RI pin.These answers should cover the most common questions regarding the SIM800C module. If you need further details or have additional questions, feel free to ask!